Measurement Period for Beam Reporting

ABSTRACT

In NR, a gNB utilizes multiple antennas and beam forming techniques for downlink transmissions to UEs. Described herein are methods and apparatus by which a UE measures the quality of multiple directional beams received from a gNB.

PRIORITY CLAIM

This application claims priority to U.S. Provisional Pat. ApplicationSerial No. 62/717,708 filed Aug. 10, 2018 which is hereby incorporatedby reference in its entirety.

TECHNICAL FIELD

Embodiments described herein relate generally to wireless networks andcommunications systems. Some embodiments relate to cellularcommunication networks including 3GPP (Third Generation PartnershipProject) networks, 3GPP LTE (Long Term Evolution) networks, 3GPP LTE-A(LTE Advanced), and 3GPP fifth generation (5G) or new radio (NR)networks, although the scope of the embodiments is not limited in thisrespect.

BACKGROUND

In Long Term Evolution (LTE) and next generation new radio (NR) systems,a mobile terminal (referred to as a User Equipment or UE) connects tothe cellular network via a base station (referred to as an evolved NodeB or eNB or as a next generation Node B or gNB). In NR, a gNB utilizesmultiple antennas and beam forming techniques for downlink transmissionsto UEs. Described herein are methods and apparatus by which a UEmeasures the quality of multiple directional beams received from a gNB.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example UE and a base station (BS) such as an eNBor gNB according to some embodiments.

FIG. 2 illustrates an example measurement model for producing beamreports.

DETAILED DESCRIPTION

In Long Term Evolution (LTE) and 5G systems, a mobile terminal (referredto as a User Equipment or UE) connects to the cellular network via abase station (BS), referred to as an evolved Node B or eNB in LTEsystems and as a next generation evolved Node B or gNB in 5G or NRsystems. FIG. 1 illustrates an example of the components of a UE 1400and a base station (e.g., eNB or gNB) 1300. The BS 1300 includesprocessing circuitry 1301 connected to a radio transceiver 1302 forproviding an air interface. The UE 1400 includes processing circuitry1401 connected to a radio transceiver 1402 for providing an airinterface over the wireless medium. Each of the transceivers in thedevices is connected to antennas 1055. The antennas 1055 of the devicesform antenna arrays whose directionality may be controlled by theprocessing circuitry. The memory and processing circuitries of the UEand/or BS may be configured to perform the functions and implement theschemes of the various embodiments described herein.

The NR waveform is based on orthogonal frequency division multiplexing(OFDM) with variable numerology (i.e., subcarrier spacing). The NRtime-domain structure has a 10-ms radio frame divided into ten 1-mssubframes. A subframe is in turn divided into slots consisting of 14OFDM symbols. The duration of a slot in milliseconds depends on thenumerology.

The air interface for NR, also referred to as the radio interface orradio access network (RAN), has a layered protocol architecture wherepeer layers of the UE and gNB pass protocol data units (PDUs) betweeneach other that are encapsulated service data units (SDUs) of the nexthigher layer. The topmost layer in the user plane is the Service DataApplication Protocol (SDAP) which is responsible for mapping QoS(quality-of-service) bearers to radio bearers according to theirquality-of-service requirements. The next lower layers are the packetdata compression protocol (PDCP) that transmits and receives IP(internet protocol) packets and the Radio-Link Control (RLC) layerresponsible for segmentation and

retransmission handling. The PDCP layer communicates with the radio linkcontrol (RLC) layer via radio bearers to which IP packets are mapped. Atthe medium access control (MAC) layer, the connection to the RLC layerabove is through logical channels, and the connection to the physicallayer below is through transport channels. The primary UL transportchannel is the uplink shared channel (UL-SCH), and the primary DLtransport channel is the downlink shared channel (DL-SCH). Another DLtransport channel, the broadcast channel (BCH), is used by the gNB tobroadcast system information. At the physical layer, the UL-SCH isassociated with the physical uplink shared channel (PUSCH), the DL-SCHis associated with the physical downlink shared channel (PDSCH), and theBCH is associated with the physical broadcast channel (PBCH). Thecontrol plane protocol layers are the same as for the user plane exceptthat the topmost layer of the control plane in the access stratumbetween the UE and gNB is the radio resource control (RRC) layer inplace of the SDAP layer. The physical layer is referred to as layer 1 orL1. The MAC, RLC, and PDCP layers are referred to as layer 2 or L2. TheRRC layer, as well as the nonaccess stratum (NAS) layer between the UEand the core network in the control plane and user applications in theuser plane, are referred to layer 3 or L3.

In order to perform scheduling and other link adaptation functions, thegNB needs to know the downlink channel from the BS to the UE. LTE andNR. provides reference signals that may be used by a UE to obtaindownlink channel state information (CSI) for a transmitting cell,referred to as channel state information reference signals (CSI-RSs).The UE may then feedback the CSI thus obtained to the serving cell inthe form of a CSI report. CSI-RS are transmitted using particulartime-frequency resource element (REs) of an orthogonal frequencydivision multiple access (OFDMA) transmission scheme over the physicaldownlink shared channel (PDSCH) with a configurable periodicity andspanning the entire transmit band. Multiple sets of CSI-RSs may betransmitted by a cell with each set corresponding to a different antennaport. A UE may use the CSI-RSs to estimate the channel and produce a CSIreport that is fed back to the serving cell either multiplexed with dataover the PDSCH or via the physical uplink control channel (PUCCH). Forperiodic CSI reporting, the CSI report is encoded with a forward errorcorrection (FEC) such as a polar code and sent over the PUCCH.

Both NR and LTE provide for multi-antenna transmission and receptionwhere multi-input multi-output (MIMO) precoding and MIMO decoding areperformed in the digital domain at baseband. At mm Wave frequencies(above 6 Ghz, referred to as FR2) used by NR, however, it iscontemplated that the antenna processing will be carried out in theanalog or hybrid digital-analog domain on a carrier basis. This meansthat downlink transmissions to different UEs located in differentdirections relative to the gNB must be separated in time. Likewise, inthe case of analog-based receiver-side beam-forming, the receive beamcan only focus in one direction at a time. Beam management refers to theestablishment and retention of a suitable beam pair made up of atransmitter-side beam direction and a corresponding receiver-side beamdirection that jointly provide good connectivity.

In NR implementations, beam management refers to a set of L1/L2procedures to acquire and maintain a set of transmission/reception point(TRP), where a TRP may be a gNB, and/or UE beams that can be used fordownlink (DL) and uplink (UL) transmission/reception. Beam managementincludes various operations or procedures, such as beam determination,beam management, beam reporting, and beam sweepingoperations/procedures. Beam determination refers to TRP(s) or UE abilityto select of its own transmission (Tx)/reception (Rx) beam(s). Beammeasurement refers to TRP or UE ability to measure characteristics ofreceived beamformed signals. Beam reporting refers the UE ability toreport information of beamformed signal(s) based on beam measurement.Beam sweeping refers to operation(s) of covering a spatial area, withbeams transmitted and/or received during a time interval in apredetermined manner.

Tx/Rx beam correspondence at a TRP holds if at least one of thefollowing conditions are satisfied: TRP is able to determine a TRP Rxbeam for the uplink reception based on UE’s downlink measurement onTRP’s one or more Tx beams; and TRP is able to determine a TRP Tx beamfor the downlink transmission based on TRP’s uplink measurement on TRP’sone or more Rx beams. Tx/Rx beam correspondence at a UE holds if atleast one of the following is satisfied: UE is able to determine a UE Txbeam for the uplink transmission based on UE’s downlink measurement onUE’s one or more Rx beams; UE is able to determine a UE Rx beam for thedownlink reception based on TRP’s indication based on uplink measurementon UE’s one or more Tx beams; and Capability indication of UE beamcorrespondence related information to TRxP is supported.

In some implementations, DL beam management includes procedures P-1,P-2, and P-3. Procedure P-1 is used to enable UE measurement ondifferent TRP Tx beams to support selection of TRP Tx beams/UE Rxbeam(s). For beamforming at TRP, procedure P-1 typically includes aintra/inter-TRP Tx beam sweep from a set of different beams. Forbeamforming at the UE, procedure P-1 typically includes a UE Rx beamsweep from a set of different beams.

Procedure P-2 is used to enable UE measurement on different TRP Tx beamsto possibly change inter/intra-TRP Tx beam(s). Procedure P-2 may be aspecial case of procedure P-1 wherein procedure P-2 is used for apossibly smaller set of beams for beam refinement than procedure P-1.Procedure P-3 is used to enable UE measurement on the same TRP Tx beamto change UE Rx beam in the case UE uses beamforming. Procedures P-1,P-2, and P-3 may be used for aperiodic beam reporting.

UE measurements based on RS for beam management (at least CSI-RS) iscomposed of K beams (where K is a total number of configured beams), andthe UE reports measurement results of N selected Tx beams (where N mayor may not be a fixed number). The procedure based on RS for mobilitypurpose is not precluded. Beam information that is to be reportedincludes measurement quantities for the N beam(s) and informationindicating N DL Tx beam(s), if N < K. Other information or data may beincluded in or with the beam information. When a UE is configured withK′ >1 non-zero power (NZP) CSI-RS resources, a UE can report N′ CSI-RSResource Indicator (CRIs).

In some NR implementations, a UE can trigger a mechanism to recover frombeam failure, which is referred to a “beam recovery”, “beam failurerecovery request procedure”, and/or the like. A beam failure event mayoccur when the quality of beam pair link(s) of an associated controlchannel falls below a threshold, when a time-out of an associated timeroccurs, or the like. The beam recovery mechanism is triggered when beamfailure occurs. The network may explicitly configure the UE withresources for UL transmission of signals for recovery purposes.Configurations of resources are supported where the base station (e.g.,a TRP, gNB, or the like) is listening from all or partial directions(e.g., a random access region). The UL transmission/resources to reportbeam failure can be located in the same time instance as a PhysicalRandom Access Channel (PRACH) or resources orthogonal to PRACHresources, or at a time instance (configurable for a UE) different fromPRACH. Transmission of DL signal is supported for allowing the UE tomonitor the beams for identifying new potential beams.

For beam failure recovery, a beam failure may be declared if one,multiple, or all serving PDCCH beams fail. The beam failure recoveryrequest procedure is initiated when a beam failure is declared. Forexample, the beam failure recovery request procedure may be used forindicating to a serving gNB (or TRP) of a new SSB or CSI-RS when beamfailure is detected on a serving SSB(s)/CSI-RS(s). A beam failure may bedetected by the lower layers and indicated to a Media Access Control(MAC) entity of the UE.

In some implementations, beam management includes providing or notproviding beam-related indications. When beam-related indication isprovided, information pertaining to UE-side beamforming/receivingprocedure used for CSI-RS-based measurement can be indicated through QCLto the UE. The same or different beams on the control channel and thecorresponding data channel transmissions may be supported.

Downlink (DL) beam indications are based on a Transmission ConfigurationIndication (TCI) state(s). The TCI state(s) are indicated in a TCI listthat is configured by radio resource control (RRC) and/or Media AccessControl (MAC) Control Element (CE). In some implementations, a UE can beconfigured up to M TCI-States by higher layer signaling to decode PDSCHaccording to a detected PDCCH with downlink control information (DCI)intended for the UE and the given serving cell where M depends on the UEcapability. Each configured TCI state includes one reference signal (RS)set TCI-RS-SetConfig. Each TCI-RS--SetConfig includes parameters forconfiguring quasi co-location relationship(s) between the RSs in the RSset and the demodulation reference signal (DM-RS) port group of thePDSCH. The RS set includes a reference to either one or two DL RSs andan associated quasi co-location type (QCL-Type) for each DL RS(s)configured by the higher layer parameter QCL-Type. For the case of twoDL RSs, the QCL types shall not be the same, regardless of whether thereferences are to the same DL RS or different DL RSs. The quasico-location types indicated to the UE are based on the higher layerparameter QCL-Type and take one or a combination of the following types:QCL-TypeA: {Doppler shift, Doppler spread, average delay, delay spread};QCL-TypeB: {Doppler shift, Doppler spread}; QCL-TypeC: {average delay,Doppler shift}; QCL-TypeD: {Spatial Rx parameter}.

The UE may receive a selection command (e.g., in a MAC CE), which isused to map up to 8 TCI states to the codepoints of the DCI fieldTCI-states. Until a UE receives higher layer configuration of TCI statesand before reception of the activation command, the UE may assume thatthe antenna ports of one DM-RS port group of PDSCH of a serving cell arespatially quasi co-located with the SSB determined in the initial accessprocedure. When the number of TCI states in TCI-States is less than orequal to 8, the DCI field TCI-states directly indicates the TCI state.

A beam failure recovery request could be delivered over dedicated PRACHor Physical Uplink Control Channel (PUCCH) resources. For example, a UEcan be configured, for a serving cell, with a set

of periodic CSI-RS resource configuration indexes by higher layerparameter Becim-Failitre-Detection-RS-ResourceConfig and with a set

of CSI-RS resource configuration indexes and/or SS/PBCH block indexes byhigher layer parameter Candidate-Betini-RS-List for radio link qualitymeasurements on the serving cell. If there is no configuration, the beamfailure detection could be based on CSI-RS or SSB, which is spatiallyQuasi Co-Located (QCLed) with the PDCCH Demodulation Reference Signal(DMRS). For example, if the UE is not provided with the higher layerparameter Beam-Failure-Detection-RS-ResourceConfig, the UE determines toinclude SS/PBCH blocks and periodic CSI-RS configurations with samevalues for higher layer parameter TCI-StatesPDCCH as for controlresource sets (CORESET) that the UE is configured for monitoring PDCCH.

The physical layer of a UE assesses the radio link quality according toa set

of resource configurations against a threshold Q_(out,LR). The thresholdQ_(out,LR) corresponds to a default value of higher layer parameterRLM-IS-OOS-thresholdConfig and Beam-failure-eandidate-beam-threshold,respectively. For the set

the UE assesses the radio link quality only according to periodic CSI-RSresource configurations or SS/PBCH blocks that are quasi co-located,with the DM-RS of PDCCH receptions DM-RS monitored by the UE. The UEapplies the configured Q_(in,LR) threshold for the periodic CSI-RSresource configurations. The UE applies the Q_(out),_(LR) threshold forSS/PBCH blocks after scaling a SS/PBCH block transmission power with avalue provided by higher layer parameter Pc_SS.

In some implementations, if a beam failure indication has been receivedby a MAC entity from lower layers, then the MAC entity starts a beamfailure recovery timer (beamFailureRecoveryTimer) and initiates a RandomAccess procedure. If the beamFailureRecoveryTimer expires, then the MACentity indicates a beam failure recovery request failure to upperlayers. If a DL assignment or UL grant has been received (e.g., on aPDCCH addressed for a cell radio network temporary identifier (C-RNTI)),then the MAC entity may stop and reset beamFailureRecoveryTimer andconsider the beam failure recovery request procedure to be successfullycompleted.

In embodiments, a UE (e.g., in RRC_CONNTCTED mode) measures one ormultiple beams of a cell and the measurement results (power values) areaveraged to derive the cell quality. The UE may be configured toconsider a subset of the detected beams, such as the N best beams abovean absolute threshold. Filtering takes place at two different levelsinclude at the physical layer (PHY) to derive beam quality and then atthe RRC level to derive cell quality from multiple beams. Cell qualityfrom beam measurements may be derived in the same way for the servingcell(s) and for the non-serving cell(s). Measurement reports contain themeasurement results of the X best beams if the UE is configured to do soby the gNB. For channel state estimation purposes, the UE may beconfigured to measure CSI-RS resources and estimate a downlink channelstate based on the CSI-RS measurements. The UE feeds the estimatedchannel state back to the gNB to be used in link adaptation.

An example measurement model is shown by FIG. 2 . In FIG. 2 , point Aincludes measurements (e.g., beam specific samples) internal to the PHY.Layer 1 (L1) filtering includes internal layer 1 filtering circuitry forfiltering the inputs measured at point A. The exact filtering mechanismsand how the measurements are actually executed at the PHY may beimplementation specific. The measurements (e.g., beam specificmeasurements) are reported by the L1 filtering to layer 3 (L3) beamfiltering circuitry and the beam consolidation/selection circuitry atpoint A¹.

The Beam Consolidation/Selection circuitry includes circuitry where beamspecific measurements are consolidated to derive cell quality. Forexample, if N > 1, else when N = 1 the best beam measurement may beselected to derive cell quality. The configuration of the beam isprovided by RRC signaling. A measurement (e.g., cell quality) derivedfrom the beam-specific measurements are then be reported to L3 filteringfor cell quality circuitry after beam consolidation/selection. In someembodiments, the reporting period at point B may be equal to onemeasurement period at point A¹.

The L3 filtering for cell quality circuitry is configured to filter themeasurements provided at point B. The configuration of the Layer 3filters is provided by the aforementioned RRC signaling ordifferent/separate RRC signaling. In some embodiments, the filteringreporting period at point C may be equal to one measurement period atpoint B. A measurement after processing in the layer 3 filter circuitryis provided to the evaluation of reporting criteria circuitry at pointC. In some embodiments, the reporting rate may be identical to thereporting rate at point B. This measurement input may be used for one ormore evaluation of reporting criteria.

Evaluation of reporting criteria circuitry is configured to checkwhether actual measurement reporting is necessary at point D. Theevaluation can be based on more than one flow of measurements atreference point C. In one example, the evaluation may involve acomparison between different measurements, such as a measurementprovided at point C and another measurement provided at point C¹. Inembodiments, the UE may evaluate the reporting criteria at least everytime a new measurement result is reported at point C, C¹. The reportingcriteria configuration is provided by the aforementioned RRC signaling(UE measurements) or different/separate RRC signaling. After theevaluation, measurement report information (e.g., as a message) is senton the radio interface at point D.

Referring back to point A¹, measurements provided at point A¹ areprovided to L3 Beam filtering circuitry, which is configured to performbeam filtering of the provided measurements (e.g., beam specificmeasurements). The configuration of the beam filters is provided by theaforementioned RRC signaling or different/separate RRC signaling. Inembodiments, the filtering reporting period at point E may be equal toone measurement period at A¹. The K beams may correspond to themeasurements on New Radio (NR)-synchronization signal (SS) block (SSB)or Channel State Information Reference Signal (CSI-RS) resourcesconfigured for L3 mobility by a gNB and detected by the UE at L1.

After processing in the beam filter measurement (e.g., beam-specificmeasurement), a measurement is provided to beam selection for reportingcircuitry at point E. This measurement is used as an input for selectingthe X measurements to be reported. In embodiments, the reporting ratemay be identical to the reporting rate at point A¹. The beam selectionfor beam reporting circuitry is configured to select the X measurementsfrom the measurements provided at point E. The configuration of thismodule is provided by the aforementioned RRC signaling ordifferent/separate RRC signaling. The beam measurement information to beincluded in a measurement report is sent or scheduled for transmissionon the radio interface at point F.

The measurement reports include a measurement identity of an associatedmeasurement configuration that triggered the reporting. The measurementreports may also include cell and beam measurement quantities to beincluded in measurement reports that are configured by the network(e.g., using RRC signaling). The measurement reports may also includenumber of non-serving cells to be reported can be limited throughconfiguration by the network. Cell(s) belonging to a blacklistconfigured by the network are not used in event evaluation andreporting. By contrast, when a whitelist is configured by the network,only the cells belonging to the whitelist are used in event evaluationand reporting. The beam measurements to be included in measurementreports are configured by the network, and such measurement reportsinclude or indicate a beam identifier only, a measurement result, andbeam identifier, or no beam reporting.

The current measurement period for beam reporting is not clear for NRsystems. Embodiments herein provide a measurement period of periodicCSI-RS based L1-RSRP and aperiodic CSI-RS based L1-RSRP for beamreporting. According to various embodiments, for periodic CSI-RS basedL1-RSRP, there are two options for a measurement period:

-   Option 1: No time domain averaging of L1-RSRP measurements are    performed on UE side;-   Option 2: L1 averaging with X samples are assumed.

For option 1, it is assumed that the IJE will apply the beam reportingbased on a single slot, and it is left to gNB to perform measurementaveraging. However, there are some drawbacks for the report to be basedon single slot. If there are multiple Tx beams, e.g. 16/32 beams, and UEis requested to report up to 4 beams, the UE will choose 4 beams justbased on the single slot measurement. If the single slot measurementaccuracy is not good enough, the correct beam may not be chosen.Simulation results based on single sample have demonstrated that themeasurement accuracy is bad at some scenarios and the correct beamcannot be chosen.

Simulation results have shown that the measurement accuracy is dependenton the CSI-RS density, bandwidth, channel model and subcarrier spacing.For single sample, the measurement accuracy is not good even for SNR=0dB on some cases. For example, the single sample accuracy may be largerthan 2.5 dB for the ETU channel model, 24RB with D=⅓ in the ETU channeland 96RB with D=1 in the ETU channel model. L1-RSRP accuracy with ±2.5dB can only guarantee that the reported beam can be within the best ⅝/12beams out of a total of 8/16/32 beams, respectively, in 90% of casesrespectively. The accuracy requirement will be even more stringent ifbetter beam reporting quality is needed.

The reported beams will change for different report time and it isdifficult for the gNB to average the measurement results. For somebeams, there may be only one reporting result that cannot be averaged.If the gNB waits for some time to get the result of multiple beams, thedelay may be large. Therefore, for the UE side, it is better to do somekind of averaging to help improve the reporting quality.

If the CSI-RS beam reporting interval and beam measurement period areidentical, there will always be enough samples for averaging during themeasurement period. However, if CSI-RS beam reporting interval is lessthan beam measurement period, there maybe not enough samples foraveraging. A sliding window may be applied in those cases for sampleaveraging.

For aperiodic CSI-RS based L1-RSRP, if single sample measurement isapplied, the UE may receive DCI at time n, and it will send out beamreporting at n+M , where M is the measurement delay for single sample.However, since single sample measurement would not provide enoughaccuracy, multiple samples averaging is needed. Suppose X samples areneeded for averaging. The gNB can send out candidate Tx beams for Xtimes after it sends out the DCI. The UE will send the beam reportingonly when it finishes averaging the X samples. If the UE receives theDCI at time n, it will send out beam reports at n+P, where P is themeasurement delay for multiple samples averaging. The report delay maybe extended for the multiple samples averaging case compared with singlesample case.

In Example 1, an apparatus for a user equipment (UE) comprises: memoryand processing circuitry, wherein, the processing circuitry is to:measure reference signal received power (RSRP) of one or more channelstate information reference signals (CSI-RSs), where the CSI-RSs aretransmitted from a next generation evolved node B (gNB) via differentdirectional beams; for a particular directional beam, average aplurality of RSRPs for the CSI-RS associated with that particular beamreceived at different times; and, encode a beam report for sending tothe gNB that includes the average RSRP of one or more CSI-RSs associatedwith one or more beams.

The processing circuitry may be to periodically encode the beam reportfor sending to the gNB in accordance with a reporting period, where thereporting period may be specified by the gNB. The processing circuitrymay be to apply a sliding window for averaging when the reporting periodis less than a beam measurement period needed for averaging. Theprocessing circuitry may be to encode the beam report for sending to thegNB in response to downlink control information (DCI) received from thegNB over a physical downlink control channel (PDCCH). The processingcircuitry may be to average a number N RSRPs for the beam report, wherethe number N is received from the gNB. The processing circuitry may beto average a plurality of RSRPs for the beam report from a CSI-RSreceived in different slots.

In Example 2, an apparatus for a next generation evolved Node B (gNB),the apparatus comprises: memory and processing circuitry, wherein, theprocessing circuitry is to encode instructions for sending to a userequipment (UE) that instruct the UE to: measure reference signalreceived power (RSRP) of one or more channel state information referencesignals (CSI-RSs), where the CSI-RSs are transmitted from the gNB viadifferent directional beams; for a particular directional beam, averagea plurality of RSRPs for the CSI-RS associated with that particular beamreceived at different times; and, encode a beam report for sending tothe gNB that includes the average RSRP of one or more CSI-RSs associatedwith one or more beams. The processing circuitry may be to encodeinstructions that instruct the UE to periodically encode the beam reportfor sending to the gNB in accordance with a reporting period. Theprocessing circuitry may be to encode instructions that instruct the UEto apply a sliding window for averaging when the reporting period isless than a beam measurement period needed for averaging. The processingcircuitry may be to encode instructions that instruct the UE to encodethe beam report for sending to the gNB in response to downlink controlinformation (DCI) received from the gNB over a physical downlink controlchannel (PDCCH). The processing circuitry may be to encode instructionsthat instruct the UE to average a number N RSRPs for the beam report,where the number N is received from the gNB. The processing circuitrymay be to encode instructions that instruct the UE to average aplurality of RSRPs for the beam report from a CSI-RS received indifferent slots.

In Example 3, a non-transitory computer-readable storage mediumcomprises instructions to cause processing circuitry of a UE or gNB,upon execution of the instructions by the processing circuitry, toperform any of the function recited in Examples 1 and 2.

The above detailed description refers to the accompanying drawings. Thesame reference numbers may be used in different drawings to identify thesame or similar elements. In the above description, for purposes ofexplanation and not limitation, specific details are set forth such asparticular structures, architectures, interfaces, techniques, etc. inorder to provide a thorough understanding of the various aspects ofvarious embodiments. However, it will be apparent to those skilled inthe art having the benefit of the present disclosure that the variousaspects of the various embodiments may be practiced in other examplesthat depart from these specific details. In certain instances,descriptions of well-known devices, circuits, and methods are omitted soas not to obscure the description of the various embodiments withunnecessary detail. For the purposes of the present document, the phrase“A or B” means (A), (B), or (A and B).

The embodiments as described above may be implemented in varioushardware configurations that may include a processor for executinginstructions that perform the techniques described. Such instructionsmay be contained in a machine-readable medium such as a suitable storagemedium or a memory or other processor-executable medium.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with others. Otherembodiments may be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is to allow thereader to quickly ascertain the nature of the technical disclosure. Itis submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims. Also, in theabove Detailed Description, various features may be grouped together tostreamline the disclosure. However, the claims may not set forth everyfeature disclosed herein as embodiments may feature a subset of saidfeatures. Further, embodiments may include fewer features than thosedisclosed in a particular example. Thus, the following claims are herebyincorporatedinto the Detailed Description, with a claim standing on itsown as a separate embodiment.

1-18. (canceled)
 19. An apparatus for a user equipment (UE), the apparatus comprising: memory and processing circuitry, wherein, the processing circuitry is configured to: for each of one or more beams, measure Layer 1 reference signal received power (L1-RSRP) of one or more channel state information reference signals (CSI-RSs) during a beam measurement period for L1-RSRP measurements, where the CSI-RSs are transmitted from a base station (BS) via different directional beams, wherein the beam measurement period for L1-RSRP measurements spans multiple time slots and is larger than a beam reporting interval; and encode a beam report for sending to the BS that includes, for each of the one or more beams, the corresponding L1-RSRP of the corresponding CSI-RS measured over the beam measurement period for L1-RSRP measurements.
 20. The apparatus of claim 19, wherein the processing circuitry is configured to periodically encode the beam report for sending to the BS in accordance with the beam measurement period for L1_RSRP measurements.
 21. The apparatus of claim 20 wherein the processing circuitry is configured to apply a sliding window for averaging a plurality of L1-RSRP measurements.
 22. The apparatus of claim 19, wherein the processing circuitry is configured to encode the beam report for sending to the BS in response to downlink control information (DCI) received from the BS over a physical downlink control channel (PDCCH).
 23. The apparatus of claim 19, wherein the processing circuitry is configured to average a number N L1-RSRPs for the beam report, where the number N is received from the BS.
 24. The apparatus of claim 19, wherein the processing circuitry is configured to average a plurality of L1-RSRPs for the beam report from a CSI-RS received in different slots.
 25. The apparatus of claim 19, further comprising: antennas; and a transceiver coupled to the antennas and to the processing circuitry.
 26. The apparatus of claim 19, wherein the base station is a gNodeB of 3GPP 5G New Radio.
 27. A non-transitory computer-readable storage medium comprising instructions to cause processing circuitry of a user equipment (UE), upon execution of the instructions by the processing circuitry, to: for each of one or more beams, measure Layer 1 reference signal received power (L1-RSRP) of one or more channel state information reference signals (CSI-RSs) during a beam measurement period for L1-RSRP measurements, where the CSI-RSs are transmitted from a base station (BS) via different directional beams, wherein the beam measurement period for L1-RSRP measurements spans multiple time slots and is larger than a beam reporting interval; and encode a beam report for sending to the BS that includes, for each of the one or more beams, the L1-RSRP of the corresponding CSI-RS measured over the beam measurement period for L1-RSRP measurements.
 28. The non-transitory computer-readable storage medium of claim 27 further comprising instructions to periodically encode the beam report for sending to the BS in accordance with the beam measurement period for L1­_RSRP measurements.
 29. The non-transitory computer-readable storage medium of claim 28 further comprising instructions to apply a sliding window for averaging a plurality of L1-RSRP measurements.
 30. The non-transitory computer-readable storage medium of claim 27 further comprising instructions to encode the beam report for sending to the BS in response to downlink control information (DCI) received from the BS over a physical downlink control channel (PDCCH).
 31. The non-transitory computer-readable storage medium of claim 27 further comprising instructions to average a number N L 1-RSRPs for the beam report, where the number N is received from the BS.
 32. The non-transitory computer-readable storage medium of claim 27 further comprising instructions to average a plurality of L1RSRPs for the beam report from a CSI-RS received in different slots.
 33. An apparatus for a base station (BS), the apparatus comprising: memory and processing circuitry, wherein, the processing circuitry is to encode instructions for sending to a user equipment (UE) that instruct the UE to: for each of one or more beams, measure Layer 1 reference signal received power (L1-RSRP) of one or more channel state information reference signals (CSI-RSs) during a beam measurement period for L1-RSRP measurements, where the CSI-RSs are transmitted from the BS via different directional beams, wherein the beam measurement period for L1-RSRP measurements spans multiple time slots and is larger than a beam reporting interval; and, encode a beam report for sending to the BS that includes, for each of the one or more beams, the corresponding L1-RSRP of the corresponding CSI-RS measured over the beam measurement period for L1-RSRP measurements.
 34. The apparatus of claim 33 wherein the processing circuitry is to encode instructions that instruct the UE to periodically encode the beam report for sending to the BS in accordance with the beam measurement period for L1_RSRP measurements.
 35. The apparatus of claim 34 wherein the processing circuitry is to encode instructions that instruct the UE to apply a sliding window for averaging a plurality of L1-RSRP measurements.
 36. The apparatus of claim 33 wherein the processing circuitry is to encode instructions that instruct the UE to encode the beam report for sending to the BS in response to downlink control information (DCI) received from the BS over a physical downlink control channel (PDCCH).
 37. The apparatus of claim 33 wherein the processing circuitry is to encode instructions that instruct the UE to average a number N L1-RSRPs for the beam report, where the number N is received from the BS.
 38. The apparatus of claim 33 wherein the processing circuitry is to encode instructions that instruct the UE to average a plurality of L1-RSRPs for the beam report from a CSI-RS received in different slots. 